The objective of this project is to investigate local control of bone differentiation by extracellular matrix components. We have established in previous work the experimental model of bone matrix-induced cartilage and bone development. Projects currently under investigation are: 1) Purification and characterization of bone inductive proteins from bovine bone, 2) Comparative aspects of bone inductive proteins with reference to porcine bone, 3) Possible cellular source and origin of bone inductive proteins, 4) Influence of biphosphonates on cartilage and bone development and mineralization and 5) The nature of responding cells and their phenotypic potential for chondrogenesis and osteogenesis.